An air compressor is one of the most versatile tools for DIYers as well as professionals. They can power an array of air tools from staplers to large capacity paint guns. They come in handy too when you want to inflate pool stuff, a soccer ball or your vehicle’s tires.
However, you want to get the right air compressor that is able to run all the air tools you’re going to use it for, and then some. If you buy an underpowered one, then you won’t be able to run all your tools, or not continuously. On the other hand, if you choose a huge beast that can run all your tools simultaneously all day long without breaking a sweat, it might take up too much space, be impossible to move around and you’ll end up spending way more than you need to.
You’ll also want to assess many different options and specifications before deciding which air compressor suits your needs best. Remember, you’ll be blessed (or stuck, depending) with this versatile tool for a very long time. Take your time and choose wisely!
No need to be put off, we’ll help you choose the ideal air compressor to run all your tools powerfully without running out of air and without breaking the bank.
Depending on what you’re going to use it for, these are the five air compressors we recommend:
Best Car Tire Inflator
Things to Consider when Buying an Air Compressor
There is indeed a lot to consider when you’re choosing an air compressor, more than you’d imagine.
In case you’re already familiar with the subject, we’ve summed up a list of important key features to consider along with some questions you want to ask yourself before buying a new air compressor. You can find them in the short checklist immediately below.
If you’re not familiar with the subject, you will most probably be totally lost reading this checklist, but that’s okay. For those of you who are new to the subject, we’ve made an easy guide anyone can comprehend with explanations, FAQs and examples. You can find this comprehensive guide below the top best air compressors way down below in this post. You’ll be up to speed in no time!
First let’s take a quick look at the questions you want to ask yourself before buying a new air compressor, listed in our short checklist:
- Use: Do you want to use it to inflate tires, blow off dust and debris, power small or large pneumatic tools or to spray-paint?
- Frequent vs Sporadic Use: Will you use it often or just once in a while?
- Which Air Tools: Do you want to power one tool at a time or several at the same time?
- Storage Space: Can you position the air compressor in a permanent location or do you have to deploy it every time you want to use it?
- Kind: Pancake, hot dog, upright or wheelbarrow ?
- 110V vs 220V vs 460V outlet: Check if you have access to more than 110V
- Mobile or dedicated air compressor: Do you want to use it in a dedicated space, roll around the workshop or off-grid?
- Electric or combustion engine powered: Do you want to use it only indoors, outdoors or also off-grid?
- Single-stage or two-stage?
- Oil-free or oil-lubricated: maintenance free for sporadic use or oil-lubricated for intensive use?
- Air Volume (CFM): Is the CFM enough for the tools you are going to use?
- Pressure (PSI): Is 150 PSI enough for you? How much PSI do you need?
- Power (hp): Is the engine strong enough to perform its task without getting overheated?
- Tank Capacity (gal): Do you need a large tank capacity?
- Decibels (dB): Do you have to worry about sound level for family or neighbors?
If you want more information, check out our comprehensive helpful guide below this post.
How we did our review
Over the years we’ve tried and tested a lot of different air compressors to power a large array of automotive air tools: an air inflator, different spray paint guns, sand blasters, an impact wrench, an orbital sander, cut-off tools, a vacuum bleeder, a grease gun, an air drill, you name it…
We use different types of air compressors for different needs: we keep a small electric one with a carry-handle within arm’s reach for small stapling, caulking and gluing jobs, a medium size gas powered wheeled one to use off-grid and a large dedicated hulk for large air volume jobs like spray painting, sand blasting and stuff.
For this review we also dove deep in the manufacturer specifications and looked at customer reviews to see what their experience was. We only recommend automotive air compressors that did an excellent job for us and the vast majority of other car enthusiasts. We’ve selected air compressors for different purposes, to make it easy for you to choose the right one for your garage, tool shed, flatbed or pickup, depending on what you intend to use it for.
CCM’s Top 5 Best Air Compressors
- Type: Upright
- Recommended for: Inflation, angle grinder, cut-off tool, impact wrenches, drill, hammer, sander, polisher, shears, grease/caulking gun,…
- Power Source: Corded Electric 120V
- Mobile: Yes
- Wheeled: Yes
- Air Volume / CFM: 5 CFM @ 90PS
- Maximum Pressure / PSI: 150 PSI
- Tank Capacity / Gal: 20 Gal
- Noise Level: 68 dB
- Maintenance Free: Yes
- Single Stage or Two Stage: Single stage
- Dimensions: 20” x 18” x 42”
- Strong handle with grip for easy carrying
If you’re looking for a do-it-all, wheeled, ultra quiet, medium size compressor, this one ticks all your boxes at a price that’s hard to match.
Its high quality induction motor generates 1.8 HP at 68 dB which is 80% quieter than standard motors. It has up to 3 times greater longevity too.
With a peak of 150 PSI, 6 CFM @ 40 PSI and 5 CFM @ 90 PSI and a tank capacity of 20 GAL, you can use it to power a paint gun, a nail gun, an angle grinder, a cut-off tool, impact wrenches, a drill hammer, a sander, a polisher,… and you can inflate that swimming pool flamingo too.
Despite its capabilities, it is still easy to roll around on its big 8” reinforced rubber wheels because of its ergonomic upright construction with a protective cage and soft handle on top. It is easy to use with its top mounted control panel with two gauges that show tank and tool pressure, managed by a regulator, and two quick-connectors.
Customers agree that this compact mobile air compressor is very quiet and that you get a lot of value for the money. They say that it doesn’t take up much space either.
We think that this mid-size upright wheeled compressor is the ideal compromise between a light portable pancake style air compressor and a dedicated large capacity workshop power house. It can even power medium to high CFM tools if needed, but it can still be rolled around with astonishing ease.
May the quiet force be with you…
- Up to 80% quieter (68 dB)
- Powerful 1.8 HP quality induction motor
- Up to 3x greater longevity
- 150 PSI, 6 CFM @ 40 PSI, 5 CFM @ 90 PSI
- Can power all your tools
- Large 8” reinforced rubber wheels
- Handy control panel
- Dual quick-connect
- Doesn’t fit underneath your average workbench
- Must be transported, stored and used in the upright position
- Type: Pancake
- Recommended for: Air brushing, small stapling, grease gun, caulking, and gluing jobs
- Power Source: Corded Electric 120V
- Mobile: Yes
- Wheeled: No
- Air Volume / CFM: 2.6 SCFM @ 90 PSI
- Maximum Pressure / PSI: 150 PSI
- Tank Capacity / Gal: 6 Gal
- Noise Level: 78.5 dB
- Maintenance / Oil Free: Yes
- Single Stage or Two Stage: Single Stage
- Dimensions: 16.5” x 16.5” x 17.88”
This awesome budget deal does what it says on the box: it’s ultra portable, lightweight, oil-free and delivers 2.6 SCFM at 90 PSI with a maximum of 150 PSI. Its double coupler allows two tools to connect at once.This durable maintenance-free 6 GAL compressor is proudly made in Jackson, Tennessee.
It comes with a 13 pcs accessory set including a 1/4” PVC air hose with coupler and plug, a tire chuck with plug, a blow gun with plug, a tire gauge, a blow gun with OSHA safety nozzle, a rubber tip and three inflator adaptors.
If you’re looking for a small compressor to power an air stapler, small nail gun, inflate tires, balls,… or do a small spray paint job, this little guy won’t disappoint! It’s the perfect versatile driveway sidekick for a ridiculous price.
Customers say that it doesn’t take much room, it’s light and easy to move around. They like the fact that it comes with all the basic accessories, which most do not include. They say it’s great value for the money.
We love to use this pancake air compressor for little jobs like small air paint touch-ups, gluing and for our air powered grease gun. It makes more sense than having to deploy the big guns and connect and disconnect hoses and stuff for a job that is only just a couple of minutes of work. You just take it off the shelf, plug it in the wall outlet and you’re good to go.
- Ultra portable
- The perfect sidekick for small jobs
- Delivers 2.6 SCFM at 90 PSI with a maximum of 150 PSI
- 13 pcs accessory set included
- 6 GAL tank
- Double coupler
- Made in the USA
- With 78.5 dB you’ll know it’s there
- Not meant to power higher (S)CFM rated tools
- Type: Tire inflator
- Recommended for: Inflating tires, sport balls, pool toys…
- Power Source: car power outlet (DC 12V)
- Mobile: Yes
- Wheeled: No
- Air volume / CFM: n/a
- Maximum Pressure / PSI: 150 PSI
- Tank Capacity / Gal: n/a
- Noise Level: n/a
- Maintenance / Oil Free: Oil-Free
- SIngle Stage or Two Stage: Single Stage
- Dimensions: 7.64” x 6.14” x 2.95”
Want something simple, compact and budget-friendly just to top up your car tires? Want to take it with you everywhere just in case? This little guy does an awesome job!
Its compact, snug carrying case protects it from dust while not in use. The sturdy plastic body looks the part and it is available with blue or red accents or just plain black. All cables are neatly tucked away in a compartment underneath.
Always ready when you need it, just plug it in your car’s 12V cigarette lighter socket (120W-10A). The display lights up and there’s an emergency light just in case. Select the desired PSI on the digital display and pop the air hose connector over the tire’s air valve. Flip the switch to “on” and it starts inflating. When the desired pressure is reached, it will automatically stop. Done!
It doesn’t get any easier than this…
Customers say they love this little inflator because it delivers what it promises: it inflates tires and more with ease at the push of a button. It does all the pumpin’ so you don’t have to.
In our experience, the digital display is very convenient to work with. Just set tire pressure, push the start button and it shuts off exactly at the desired psi. Job well done!
- Great value
- Compact size: 7.64” x 6.14” x 2.95 “
- Snug carrying case
- Lightweight (1.9 pounds)
- Illuminated digital display
- Auto stop function
- Emergency led lighting
- Easy cord and tube stow-away compartment
- Max. pressure 150 PSI
- Hose length 0.5 m / 1.64 ft
- Power cord 3.00 m / 9.84 ft
- For normal size tires, not for XL tires
- Works great for tires, not suitable to power air tools
- Type: Large Upright
- Recommended for: All air tools and applications
- Power Source: Corded Electric 220V Single Phase
- Mobile: No
- Wheels: No
- Air Volume / CFM: 10.6 CFM
- Maximum Pressure / PSI: 125 PSI
- Tank Capacity / Gal: 60 Gal
- Noise Level: 75 dB
- Maintenance / Oil Free: Yes
- Single Stage or Two Stage: Two Stage
- Dimensions: 21” x 28.5” x 66”
The new California Air Tools SP Series ultra quiet oil-free dual pump air compressor motors have been designed to increase duty cycle and allow for longer continuous run times. It’s engineered for high performance and durability.
The powerful dual 220 Volts 2.0 HP motors operate at only 1680 RPM creating less noise and less wear. It has a life cycle before wear of 3000+ hours. Other comparable air compressors have life cycles of less than 1500 hours.
This professional grade large capacity compressor is one of the quietest 4 HP air compressors in the industry producing only 75 db of sound. The oil-free pump allows for use in a variety of temperatures.
The large 60 Gal steel ASME (American Society of Mechanical Engineers) air tank is just the right size for a shop or garage. Designed for the person looking for power, air flow and less service with at least 30% less noise. This big boy will power all your air tools and spray paint an entire car continuously without breaking a sweat.
Customers say it’s the quietest 4 HP air compressor they ever worked with and that it’s easy to have a conversation or hear your phone ring with the compressor running.
We like the way it can be stood in a corner without taking up too much real estate. In our experience it’s sometimes easier to have an upright compressor with a large barrel where you don’t have to bend over to reach its controls or couplings. We like it a lot!
- Professional grade quality
- Large 60 GAL ASME tank
- 4 HP (2 x 2 HP)
- 220V Single Phase
- Quiet 75 dB operation (at least 30% less noise)
- Low 1680 RPM operation for less wear
- Life cycle before wear of 3000+ hours
- Oil-free, maintenance-free dual pump
- 12.60 CFM @ 40 PSI / 10.60 CFM @ 90 PSI
- Integrated water and oil separator
- Auto drain
- Assembled in the USA by San Diego, USA based company
- Fixed, not mobile
- You need a 220V outlet
- Type: Large Hotdog
- Recommended for: Professional and DIY use / all air tools and applications
- Power Source: Corded Electric 460 Volt
- Mobile: No
- Portable: No
- Air Volume / CFM: 51 CFM
- Maximum Pressure / PSI: 175 PSI
- Tank Capacity / Gal: 120 Gal
- Noise Level: 69 dB
- Maintenance / Oil Free: No
- Single Stage or Two Stage: Two Stage
- Dimensions: 71” x 30” x 55”
Quincy Compressor was founded in 1920 in Quincy, Illinois and manufactures one of the most reliable compressors on the market for professional use. Leading the industry with the most acfm per brake horsepower, the Quincy QT™ ensures more air while consuming less energy in the production process. A one-piece aluminum head optimizes strength and dissipates heat, while Quincy’s unique valve design provides the highest volumetric efficiency available.
Quincy Air Master reciprocating air compressors are designed to be a compressor for life. They are built for efficiency and lower operating costs, producing more compressed air at a lower horsepower.
They run at a slower RPM, run cooler and cost less to operate. Heavy-duty compressors are engineered for industrial applications and boast a best-in-the-industry 50,000-hour pump life rating. They can operate continuously 24/7 without overheating.
This air compressor features “MAX configuration”, which means that automatic tank drain, low-oil shutdown and a heavy-duty aftercooler is included. With over 50 CFM, 15HP and an air tank of 120 gal., this big fella will never run out of air, for sure!
Looking for a professional quality air compressor that lasts a lifetime and longer? Don’t want to compromise? Look no further!
Quincy customers are mainly professional workshops and weekend warriors who only want the very best. You buy a Quincy compressor for life.
Our advice: if you have the space and don’t mind spending this kind of money, this is the air compressor you want.
- Professional, industrial grade quality
- Air tank size: 120 gal.
- Max. PSI: 175, working pressure: 145-175 PSI
- 51 CFM at 175 PSI, 54.4 CFM at 100 PSI
- Belt-drive 15 HP motor, 3 Phase(s), 200-230-460-575V
- 2-stage 4-cylinder pump, cast iron, one-piece aluminum head
- Pump life: 50,000 hrs.+
- Duty cycle: 100%,
- High efficiency intercooler included
- “Low Oil” protection
- Automatic drain system
- 1” air outlet
- Dimensions L x W x H (in.): 71” x 30” x 55”
- Weight: 995 Lbs
- Industrial class bearings
- Loadless auto stop/start
- Cast-iron crankcase and cylinders with aluminum heads
- Splash lubrication
- Very heavy
- Not cheap, but worth every penny
Comparison Table Of The Best Air Compressors
|Best Overall||Stealth||20 Gallon Ultra Quiet Air Compressor|
|Best Budget||Craftsman||Ultraportable Oil Free Pancake Air Compressor|
|Best Car Tire Inflator||FORTEM||Digital Tire Inflator|
|Best Semi-Professional||California Air Tools||Ultra Quiet 60 Gal Compressor|
|Best Professional||Quincy||QT-15 Splash Lubricated Air Compressor with MAX Package - 15 HP, 460 Volt, 3 Phase, 120 Gallon|
Before buying an air compressor, you want to first think long and hard about what you will be using it for, how much you will use it and how much you want to spend. If you don’t, you might regret buying that large iron deadweight for a mighty long time.
Here’s what we recommend in a nutshell:
If you’re just looking for something to top up your tires, this little guy will do just fine: Fortem Digital Tire Inflator. With its small, light design it fits in most glove boxes and is very affordable.
If you’ll also be using it to power small air tools like a blow gun, a stapler, a small nail gun, a light drill, a caulking or glue gun, a grease gun, a special paint gun, you ought to check this out: Craftsman Ultraportable Oil-Free Pancake Compressor. It’s the perfect sidekick for your big compressor too. Allways right at hand, ready to take anywhere, you’ll love it! If you ask us, it’s the most bang for your buck.
If we had to pick just one to use in any situation, this would be it: Stealth 20 Gallon Ultra Quiet Air Compressor : It’s great value, ergonomic, well built and powerful enough to do most jobs. It’s so silent you’ll hardly know it’s there. Although it’s not light, you can still roll it around your garage and driveway with its large wheels.
You can do anything with this big guy but roll it around: California Air Tools Ultra Quiet 60 Gal Compressor. Once installed, it’ll have to stay put. It’s so quiet and versatile though, that you won’t mind. It’s always ready to run when you need it. It’s arguably the closest you can get to a professional air compressor without breaking the bank.
Speaking about professional: What’s not to like about the Quincy QT-15 Splash Lubricated Air Compressor with MAX Package? This extra large, powerful beast will power all your tools with ease and won’t run out of breath, for decades to come. Powered by a 15 HP motor, it’s so well-built that even the most dedicated weekend warrior will have a hard time wearing this fine piece of machinery down.
Well folks, we’ve run out of air…
Choose wisely and enjoy!
What will you use an air compressor for?
If you just want to top up your car or (motor)bike tires, a small air compressor, even one without a pressure barrel will do.
A compact budget compressor with a small capacity pressure barrel is a better choice if you also want to use it to blow off dust and debris from your workbench or power a pneumatic stapler. It’s also suited to spray-paint small parts or surfaces with a low-capacity paint spray gun. We like to use our small handheld compressor to power caulk-, glue- and grease guns too, works great!
It’s those pneumatic tools with high RPM like a dremel tool or an angle grinder that use massive air volume. Also for an air impact wrench, a heavy nail gun, a sand blasting cabinet or to spray-paint large surfaces you’ll need an air compressor with larger air volume (CFM) .
If you’re looking for something to quickly inflate that large donut or flamingo for the swimming pool, this large volume, low pressure pump is your best choice, not a compressor. It’s also ultra portable and rechargeable Li-Ion battery powered, so you can take it anywhere.
Will you use an air compressor frequently or sporadically?
Don’t go for the cheapest air compressor if you plan to use it frequently for a longtime hobby. You’ll regret this in the long run. You want to spend some extra bucks and buy about 30% more power and capacity than what you expect to need. This way you have a margin for any large-capacity tools you might buy in the future and you won’t overstress your compressor. The saying goes: buy nice or buy twice.
On the other hand, if you’ll only be using it occasionally it may be money down the drain to buy the biggest and best. You should be aware that air compressors also age when they’re just sitting idle. Crucial internal parts will start to corrode and the pressure tank will eventually start rusting internally. Over time, grease will dry and harden and oil will age and lose its protective properties.
Which air tools do you want to power?
One of the deciding factors when choosing an air compressor is the air tools you want to use.
If you plan to use only one tool at a time, calculate the tool with the highest air volume (CFM) rating you will be using and multiply the rating by 1.5.
E.g.: if your highest CFM-rated air tool is your 1/2 inch impact wrench at 4 CFM, your compressor should be at least 6 CFM (4 x 1.5).
If you plan to work with two persons simultaneously, add the two highest CFM-rated tools you would use and multiply that number by 1.5.
E.g.: if your two highest CFM-rated air tools are your 1/2 inch impact wrench at 4 CFM and a spinning sander rated at 8 CFM, your air compressor should be at least 18 CFM ((4+8) x 1.5).
How much storage space do you have?
Don’t forget that your new toy and its accessories will take up space permanently.
You will want your air compressor positioned close at hand so it is ready to use at any time without too much hassle. If you stash it somewhere underneath a pile of stuff or in a backyard shed, you may not find the courage to unearth it when you need it for a small task. (We’ve all been there.)
Your air tools should also be within reach for the same reason. Just like you have a power outlet within reach to use your electric power tools, your compressor should also be within reach to easily connect your air tools.
A good option is to position your air compressor somewhere within a 50 to 100 ft. radius of your working area and install a fixed air pressure hose with outlet(s) that are within reach of your workspace. You can simply plug a 25 ft. air hose with a tool attached in the outlet and you’re good to go.
In this setting your compressor can even be situated outdoors, in another room, in your basement or shed and you won’t be needing earplugs anymore.
By the way: it’s generally not a good idea to encase your compressor with sound insulation, because it insulates heat too and will restrict airflow which it badly needs for cooling.
A golden rule is that effort is inversely proportional to use, when it comes to using any tool. What this means is: when a tool takes a lot of effort or time to deploy, you will hardly ever use it. You should think long and hard about that when positioning your air compressor and its accessories to get the most out of your investment.
Which type of air compressor?
The most commonly used type of compressor to power air tools or to spray-paint is a single or dual-cylinder compressor.
There are many other types of compressors like multi-stage, diaphragm, compound, rotary, rotary vane, scroll, turbo, centrifugal that are mostly used in industrial applications.
While “normal” low pressure (up to 175 PSI) workshop compressors are air cooled, these industrial types of compressors are often water cooled and can deliver 150 to 1000 PSI (medium pressure compressor) up to 1000+PSI (high pressure compressor). Again, these types of compressors are not used to power common professional air tools.
Which Kind of air compressor: Pancake, hot dog, upright or wheelbarrow?
Small, lightweight portable air compressors, often used to power small air tools like a nail gun, typically to be carried with a top mounted handle:
- Pancake style: small “UFO” or pancake style pressure tank.
- Hot dog style: small (sometimes double) sausage shaped pressure tank.
Medium to large air compressors, used for small air tools up to heavy tools (depending), typically wheeled but much less mobile and often stationary:
- Large hot dog style: air pump positioned on top of a large horizontal tank.
- Large upright style: air pump positioned on top of a large upright tank.
- Wheelbarrow style: double or sometimes single hot dog style compressor that is meant for mobile use and can be wheeled like a wheelbarrow with two side handles and one or two wheels at the opposite end. Mostly gasoline engine powered. Meant for contractors on building sites.
Do you have access to 110/120V, 220/230V or 460/480V?
If you want to buy a powerful air compressor and have access to a 220/230V power outlet, buy a 220/230V compressor instead of a 110/120V. A 460/480V air compressor can deliver even more horsepower.
220/230V can deliver twice as much amps, which means you can connect a compressor twice as powerful compared to 110/120V. (VxA=W)
If you want to also use it as a mobile unit and use it anywhere around the house, yard or other locations, you should buy a 110/120V air compressor. You will easily have access to a 110/120V power outlet anywhere in the US, while 220/230V outlets are scarce. This would limit mobility.
Because of their lower power output, 110/120V compressors will often run a more limited range of air tools, while high capacity dual stage 220/230V or 460/480V compressors can run any tool.
It is important to check if your power outlets can handle the Amps of the air compressor you want to buy. If they can’t, you’ll either have to have them rewired or buy a lower Amp compressor.
Mobile or dedicated air compressor?
Obviously some air compressors are more suitable for mobile use than others. If you’re looking for a mobile compressor, size as well as weight will be deciding factors as well as compatibility with the tools you intend to use.
It makes no sense buying a light, compact compressor that is too light for the tools you want to use. It will run out of breath quickly and will have to build up pressure again before you can continue working.
You should consider a fuel-engine powered compressor if you need a lot of power and you will mainly be using it outdoors off the grid. Generally these are mobile and more powerful than same size electric ones.
A full size dedicated compressor on the other hand can even be connected to dedicated air pressure lines with several outlets. It will run all your tools and then some, but will be nearly impossible to lug around.
It’s always a trade-off, a compromise. You can’t have a perfect all-in-one solution.That’s why professionals usually have several air compressors they can choose from, depending on the job at hand.
E.g.: A dedicated, large capacity beast in the workshop, an ultra portable pancake or wheeled upright compressor to carry or roll around to power a stapler or small nail gun where there’s electricity available and a wheelbarrow-style petrol engine powered one to power large capacity tools off-grid.
It’s up to you to decide which suits your needs best…
Do you need an electric or combustion engine powered air compressor?
This is the most black-or-white question, I guess…
Electric powered air compressors are the most popular for obvious reasons:
- cheaper than combustion engine counterparts
- no refuelling
- far less maintenance
- much more reliable
- can be used indoors
- no fumes or exhaust gasses
- quieter (most of them are)
Air compressors with a combustion engine on the other hand, can be used where or when there is no electric power available and are therefore most mobile. Generally they are more powerful compared to their size too.
What is a single-stage or two-stage air compressor?
Single-stage air compressors build pressure in one stroke, while two-stage compressors deliver pressure in two steps: The first cylinder delivers half pressured air to a second cylinder that brings it to full pressure.
Two-stage compressors are generally more expensive, but are quieter and more performant.
Do you want an oil-lubricated or oil-free air compressor?
Oil-free air compressors are pre-lubricated at the factory and need no additional maintenance or lubrication. There’s also less risk of oil contamination in the compressed air output. (more on the subject in Water and Oil Separator)
Oil-lubricated air compressors’ internals are lubricated by the oil in which the moving parts are partly submerged. For intensive, semi-professional and professional use, an oil-lubricated air compressor is advised. Though it needs fresh oil once in a while (which isn’t a big deal), it is much more durable and will greatly outlast any oil-free type.
An oil-free type is your best choice for a maintenance-free, less demanding sporadic use.
Do you need a water and oil separator?
Each air compressor blows water through its hoses as a side product. During the air compression process, air is heated and cools in the air tank and hoses. When hot air cools, it condenses, with water as a result. There are two ways for this water to come out: through the air tank bottom release valve, and through the air hose.
When it comes out the air hose, it is blown straight into the tool you are using, causing internal corrosion. To make things worse, with most compressors, especially oil-lubricated ones, oil particles are also blown through the hoses. No problem for most tools, but if you’re spray-painting, this will ruin the whole paint job, leaving ugly pimples and “fisheyes”.
Luckily you can easily solve this by installing a water and oil separator in between your air compressor and the air hose. It will catch all water and oil particles, preventing them from entering the air hose. It also has a pressure regulator, which is handy. All water and oil will collect in the bowl, which can easily be drained manually every once in a while.
Another option is to add an oil and water separator between hose and tool, but this makes your tool more bulky and obstructs free movement.
Whichever option you choose, you’ll be amazed by the amount of fluid that is collected!
Which fittings do you need?
To connect an air pressure hose to your air compressor or to connect an air pressure hose to an air tool or to another hose, an air hose quick-fitting is used.
This type of fitting can be connected and disconnected under pressure by a simple pushing or pulling motion. It has a built-in valve that automatically cuts off air pressure when disconnected, eliminating the need of first having to close a pressure valve.
There are many different styles, brands and sizes of pneumatic quick-fittings for air compressors on the market.
The standard air fitting size is 1/4”, which refers to the (approx.) inside diameter and can be 1/4” or 3/8” threaded at the hose side. E.g.: 1/4” (approx. inside diameter) x 1/4 NPT (National Pipe Thread) or 1/4” x 3/8” NPT.
Other, more specific abbreviations:
● MNPT (Male National Pipe Thread) refers to the pipe or hose connection which in this case has an outside thread.
● FNPT (Female National Pipe Thread) refers to the pipe or hose connection which in this case has an inside thread.
Two types of quick fittings are most common in the US: the industrial (M-style) and the automotive (T-style) coupling. The automotive type is a little stubbier and shorter than the industrial type, which has a thin collar near the end. Though both fittings look very similar and they both work in the same way, they normally don’t connect properly with each other.
However, the best choice for tools with high air consumption (high CFM) like grinders, large impact wrenches, paint spray guns,… are High Flow (V-style) couplings. Their much larger air channel allows much more airflow, resulting in a noticeable power increase because of less air restriction. Their female fittings are also compatible with most other types of couplings, which is a huge advantage.
All types have a male and a female side. The male side is thinner than the female coupling. The female coupling can be recognised by its thick collar that can be pulled back. The female coupling has an integrated, automatic shut-off valve that blocks airflow when disconnected.
When the male coupling is inserted in the female one with slight pressure, the female collar slides back and secures with a click, while the shut-off valve automatically opens.
“Automatic” female couplings remain in a pulled-back position when disconnected until the mail coupling is inserted, then it clicks in locked position automatically.
The non-automatic ones are in “locked position” all the time and some types have to be pulled back before they can connect. There are slight differences between different fittings and manufacturers but the general principle is the same. To disconnect, simply pull back the female collar and the male coupling pops out. When the hose is under pressure, you should hold both ends when releasing the couplings so they don’t fly off.
If you buy new air tools or air hoses, make sure they are the right type and size to connect to any existing hoses or air outlets. If not, change the fittings.
Avoid mixing different types and sizes of fittings in your tool collection. Compatibility between your tools and hoses is crucial to work efficiently without having to puzzle.
Same-type couplings from the same manufacturer are always the best choice to guarantee a perfect airtight seal.
Which air hose do you need?
Pneumatic hoses can be made of different materials, each with their drawbacks and advantages:
- Rubber: Very sturdy but heavy, lays flat easily and doesn’t kink. Higher price range. “The original” and still preferred by many professionals
- PVC: Very strong but very difficult to coil/uncoil or lay flat. Cheap hoses included with most compressors. They get very stiff in cold weather.
- PVC + rubber hybrids: Best of both worlds. Similar to rubber hoses but lighter.
- PU: Lightweight, but tangles and kinks easily, not for heavy-duty and usually a higher price range.
- Nylon: Very flexible, the lightest option, they are easy to handle but they kinks easily. Not very long-lasting.
Some air hoses come with connectors and some are threaded to accept most standard connectors. Other hoses can be cut to size and connected with barbed, 3/8” threaded inserts, secured with a hose clamp. Couplings of choice can be added.
A big advantage of these cut-to-size hoses is that you can cut them to the exact size you need. They can also be repaired easily at the coupling, where they wear the quickest. Hoses without fittings also pass through a much smaller diameter hole if you want to install a dedicated air hose through a hole in a wall or a floor for example.
Always first check compatibility. Compare prices accordingly, because connectors cost money too.
Which size of air hose do you need?
A 1/4 inch air hose will do for most air tools. In some air-guzzling applications like full-size paint guns or a heavy impact wrench, a 3/8 inch size hose or larger can provide larger air volume (CFM) because it “stores” more air and generates less drag inside the hose because air will flow at a lower speed.
A factor to consider is that 1/4” hose is lighter and easier to handle than 3/8”.
The larger the heavier, and the more difficult to handle.
Which dedicated (fixed) air hoses or air pipes?
Go for 3/8 inch size or larger for fixed dedicated hoses or pipes. Larger dedicated hoses or pipes deliver more air volume, while the larger size and weight is no disadvantage because once in place, you don’t have to manipulate them.
Dedicated hoses or pipes can be made of rubber, (soft) PVC, PVC-rubber hybrid, PU, nylon or even copper or metal.
Never use PVC plumbing pipe for dedicated air-pressure lines! Though using PVC piping is tempting because it is easily cut to size and glued together and it is very cheap, PVC pipes can explode under air pressure with dangerous sharp PVC shrapnel flying everywhere. Chances are your project would have some delay…
What do all those technical abbreviations mean?
Right below you’ll find an explanation of technical abbreviations which are commonly used in manufacturer specifications.
Air Volume (CFM)
Air volume per time unit is measured in Cubic Feet per Minute (CFM). This value says how many cubic feet of air can pass in one minute. CFM is the recognized value for measuring the airflow rate in the US. A CFM rating is normally measured at 90 PSI.
Counterintuitively, CFM value varies inversely as PSI changes. This means that when CFM goes up, PSI goes down, and vice versa.
Sometimes a SCFM (Standard Cubic Feet per Minute) value is used, which is always a higher value compared to CFM. This can be misleading. An SCFM value is measured based on ‘ideal’ temperature and pressure conditions, while CFM measures the ‘actual’ air flow rate.
The air volume you’ll need depends on the tools you’re gonna use. An average air gun uses about 7.5 CFM at 40 PSI for example.
Small pancake or hotdog compressors generally deliver sufficient pressure but fall short on CFM for large capacity tools. That’s why they are mostly rated in SCFM instead of CFM, which is a higher, more attractive rating on paper. Don’t let it fool you!
First look at what tools and how much CFM you’ll need at how many PSI. Remember that you can run higher CFM rated tools if you don’t use them continuously, as long as you have an ample air capacity tank to buffer the difference.
Simply put, working pressure, measured in PSI (Pounds per Square Inch) is the value that tells you with how much pressure or with how much power the air blows out of the hose. This is a main determining factor for the actual working power of the air tool.
Generally, the maximum pressure rating of a professional compressor is between 140 and 175 PSI. Higher isn’t always better though. It doesn’t say anything about quality or performance. Anywhere around 150 PSI maximum pressure is all you need.
As an example: small cabinet sandblasters often use pressures below 100 PSI while most air tools require between 70 and 90 PSI. Always check the manufacturer’s guidelines.
When adjusting your pressure regulator, take a close look at how it’s behaving when you use your tool. There is a big pressure drop between static pressure (when there is no air consumption) and working pressure (when the tool is being used). It’s the working pressure that matters.
Too much working pressure might damage your air tool while too little will have a negative impact on performance. Always adjust the air pressure regulator to the working pressure recommended by the manufacturer.
An air compressor is powered by a petrol or electric engine which is rated in horsepower (hp). Although there are different calculation methods, for simplicity’s sake let’s say that 1 hp is about 746 watts (W).
It is important to have an engine that is strong enough to perform its task without getting overstressed or overheated. Most, if not all, compressors are engineered to have sufficient power, so this normally should not be a primary point of concern.
Most compressors for mobile, consumer and even professional use are below 2 hp to not overload standard 110/120V electric wiring or jump a standard 15A. breaker. To run any appliance continuously, the circuit should only be used to 80% of its maximum capacity. If the 80% margin is exceeded, chances are your circuit breaker will jump when it heats up.
The maximum hp you can run on a 220/230V 20A outlet is between 4 and 5 hp, depending on the compressor’s peak current draw.
A compressor draws a peak current at startup, which exceeds its standard current draw. To reduce this peak and prevent a circuit breaker cut-out, some large compressors have a “free start valve” to allow the motor to spin freely at startup by opening the cylinders to minimize resistance.
For higher hp air compressors you will have to have a dedicated 220/230V outlet installed with a 20A breaker or an even larger gauge wiring with a higher Amp. breaker. This should be done by a certified electrician.
Regarding power, the most important indicators to evaluate if a compressor is up to the job are its CFM and PSI ratings. A compressor may be powered by a higher hp-rated engine but generate less air volume (CFM) and air pressure (PSI) than a lower hp-rated compressor that is more efficient. Look at hp as the input, while CFM and PSI are the output.
Don’t get caught up in a HP bidding war. Check how many HP you can run on the outlet you will use. Consider upgrading it if needed.
Tank Capacity (gal)
The size of the air compressor’s tank is measured in Gallons. More is better, that’s a fact when it comes to tank capacity.
An air compressor with an oversized pressure tank has a greater air reserve. Therefore it doesn’t have to cut in as often to top up air pressure as a small tank compressor would. You will be able to continuously keep working without having to wait for the compressor to catch up. The compressor will not have to start up as often and have more time to cool down in between interventions, which results in less wear and increased longevity.
Keep in mind that most air compressors are designed with a 70/30 ratio in mind: 70% running time, 30% cool down time. You’re asking for trouble if you don’t respect this ratio. Most professional (read: expensive) air compressors on the other hand, are designed to operate at 100% running time.
The obvious downside of a large tank is that it will take up more space and will be far less mobile. That’s why the degree of mobility required will have a big impact on choosing your ideal compressor.
If you’re gonna use it in situ as a dedicated compressor, you’re only limited in space, available electric power and budget. If you want to be able to move it around or even take it with you on a trailer, pickup or in a car, size and weight may urge you to compromise.
To calculate the tank capacity you need, it is recommended to multiply the maximum air volume (CFM) you’re gonna use (= your highest CFM-rated tool or tools you want to use simultaneously) at least by 2, preferably by 4.
E.g.: if your two highest CFM-rated air tools are your 1/2 inch impact wrench at 4 CFM and a spinning sander rated at 8 CFM, your air tank capacity should be between 24 GAL ((4+8) x 2) and 48 GAL ((4+8) x 4).
As long as your compressor’s CFM rating is sufficient, having a smaller tank won’t necessarily mean that your tools won’t perform well. But you will most probably be breaking the 70/30 rule, overstressing and overheating the air compressor’s components when using a high CFM tool like an air gun.
An air gun uses its full CFM continuously, unlike a stapler for example. It’s like running a car at maximum speed continuously; you might get away with it for a while but eventually you know it’s gonna cost you. Financially, that just doesn’t make sense, now does it?
As a general rule, you will only need a huge 60 GAL air tank if you want to spray paint an entire, large surface car continuously with a large capacity spray paint gun without pressure drops and with no delays. A compressor with a 60 GAL tank will also be able to supply air to several tools at once.
For all other non-professional use, a 20-30 GAL tank will be sufficient to power all your tools.
It’s often overlooked when purchasing an air compressor, but the sound level it produces will determine whether you can use your compressor on weekends and late in the evening without annoying your family or neighbors.
Even if you don’t have to worry about annoying anyone, not having to wear ear protection while working is a very solid argument too.
No, it’s nothing you can “fix” afterwards with some intake muffler or sound deadening material. The special compressor silencers you can add only take away about 2dB and sound deadening insulation also insulates heat, causing overheating.
Hate to bring it to you, but once you’ve bought an air compressor, you’re stuck with the sound it produces, period. It’s something to consider…
Low noise or silent compressors generally put out around or just below 70dB, while anything below 60dB is generally called ultra quiet. Powerful dual stage compressors are generally rated around 85dB or higher.
For comparison, a lawnmower produces around 90dB and a household vacuum cleaner between 60-85dB. dB values above 85dB are considered harmful for longtime exposure. Therefore hearing protection is advised.
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